The objective of this project is to elucidate the role of colony stimulating factor (CSF) in the modulation of granulopoiesis. The specific aims include (1) the purification and characterization of the CSF from different sources (2) the production of antibodies against the purified CSF and the establishment of a radioimmunoassay (3) the purification and characterization of the progenitor cells of granulocyte and macrophage (CFU-C) (4) the study of the mode of action of CSF on CFU-C. The CSF will be purified from human sources, particularly a human pancreatic carcinoma cell line (MIA PaCa-2) by procedures established in our laboratory. The purified CSF will be characterized biochemically, immunologically and functionally. Monospecific antibody against purified CSF will be produced in rabbits or goats and the immunological relations between different CSFs will be studied. A radioimmunoassay (RIA) will be established using the purified CSF and its antibody. The level of CSF in normal sera will be determined by RIA to establish a normal CSF profile and to exploe deviations from this normal pattern in myeloproliferative disorders. The CFU-C will be purified by photometric cell sorting methods using CSF and its antibody as specific marker. The purified CFU-C will be characterized and used to study the mode of action of CSF. Exploratory experiments wiLl be carried out to study the binding of CSF to CFU-C and the effects of CSF on macro-moleuclar synthesis. The long range objective of this project is to elucidate the role of CSF in granulopoiesis and the mechanisms of CSF-CFU-C interaction at the molecular level. Only then can we begin to examine for possible aberrations in CSF, CFU-C or their interaction in disorders of granulopoiesis. The project utilizes a multidisciplinary approach involving biochemistry, immunology, cell biology, cytology and clinical hematology.